Only 3 places it can come from..Injectors but there is usually a noticeable "skip" or miss, in the running engine.Lift pump/supply pump OR injection pump.IF you tried to bleed the air out by loosening the lines AT THE PUMP, you probably loosened the delivery valve holders.?? They need to be TORQUED back down to 30-35Ftlbs..Need to MAKE SURE its diesel fuel & not hydro fluid.